Android add()、replace()和addToBackStack()之间的差异
调用这些方法的主要区别是什么:Android add()、replace()和addToBackStack()之间的差异,android,android-fragments,Android,Android Fragments,调用这些方法的主要区别是什么: fragmentTransaction.addToBackStack(name); fragmentTransaction.replace(containerViewId, fragment, tag); fragmentTransaction.add(containerViewId, fragment, tag); 替换已经存在的片段,将片段添加到活动状态,并将活动添加到后堆栈,这意味着什么 其次,使用findFragmentByTag(),此搜索是通过add
fragmentTransaction.addToBackStack(name);
fragmentTransaction.replace(containerViewId, fragment, tag);
fragmentTransaction.add(containerViewId, fragment, tag);
替换已经存在的片段,将片段添加到活动状态,并将活动添加到后堆栈,这意味着什么
其次,使用findFragmentByTag()
,此搜索是通过add()
/replace()
方法还是通过addToBackStack()
方法添加的标记?1)fragmentTransaction.addToBackStack(str)代码>
描述-将此事务添加到后堆栈。这意味着事务将在提交后被记住,并在稍后从堆栈弹出时反转其操作
2)fragmentTransaction.replace(int-containerWebID、fragmentfragment、String标记)
描述-替换添加到容器中的现有片段。这本质上与为所有当前添加的片段调用remove(Fragment)相同,这些片段是使用相同的containerWebID添加的,然后使用此处给出的相同参数添加(int、Fragment、String)
3)fragmentTransaction.add(int-containerWebID、fragmentfragment、String标记)
Description-将片段添加到活动状态。此片段还可以选择将其视图(如果fragment.onCreateView返回非null)放入活动的容器视图中
替换已经存在的片段并添加
将一个片段添加到活动状态,并将一个活动添加到后面
堆叠
有一个堆栈,其中保存了处于运行状态的所有活动。片段属于活动。因此,您可以添加它们以将其嵌入到活动中
您可以在单个活动中组合多个片段,以构建多窗格UI,并在多个活动中重用片段。当您在不同的布局中定义了片段容器时,这非常有用。您只需要替换为任何布局中的任何其他片段
当您导航到当前布局时,您拥有该容器的id,可以将其替换为所需的片段
您还可以使用popBackStack()
方法返回backStack中的上一个片段。为此,您需要使用addToBackStack()
将该片段添加到堆栈中,然后使用commit()
进行反射。这与电流在顶部的顺序相反
findFragmentByTag搜索由添加/替换添加的标记
方法还是addToBackStack方法
If取决于您添加标记的方式。然后,它只通过您之前定义的标记查找片段,这些标记可以是从XML中膨胀的,也可以是添加到事务中时提供的
参考资料:添加和替换之间的另一个重要区别是:
replace
删除现有片段并添加新片段。这意味着当您按下后退按钮时,被替换的片段将被创建,其onCreateView
将被调用。然而,add
保留现有片段并添加新片段,这意味着现有片段将处于活动状态,并且不会处于“暂停”状态,因此当按下后退按钮时,不会为现有片段调用创建视图(添加新片段之前的片段)
就片段的生命周期事件而言,onPause
,onResume
,onCreateView
和其他生命周期事件将在replace
的情况下被调用,但在add
的情况下不会被调用
编辑:如果使用某种事件总线库,例如,并通过添加
重用同一片段来将片段堆叠在其他片段之上,则应小心。在这种情况下,即使您遵循最佳实践,在onResume
中注册事件总线并在onPause
中注销,事件总线仍将在添加片段的每个实例中处于活动状态,因为add
片段不会调用这些片段生命周期方法中的任何一个。因此,片段的每个活动实例中的事件总线侦听器将处理同一个事件,这可能不是您想要的 添加()
和替换()
之间的基本区别可以描述为:
add()
用于简单地将片段添加到某个根元素
replace()
的行为类似,但它首先删除以前的片段,然后添加下一个片段
当我们将addToBackStack()
与add()
或replace()
一起使用时,我们可以看到确切的区别
如果出现add()
,请在之后按back按钮。。。onCreateView永远不会被调用,但在replace()
的情况下,当我们按下后退按钮时。。。oncreateView每次都被调用。示例一个活动有2个片段,我们使用FragmentManager
将每个片段替换/添加到活动中的布局中
使用替换
分崩离析
分崩离析
流行音乐片段2
流行音乐片段1
使用添加
btn_one.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getActivity(),"Click First Fragment",Toast.LENGTH_LONG).show();
Fragment fragment = new SecondFragment();
getActivity().getSupportFragmentManager().beginTransaction()
// .add(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
.replace(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}
});
E/Keshav SecondFragment: onAttach
E/Keshav SecondFragment: onCreate
E/Keshav FirstFragment: onPause -------------------------- FirstFragment
E/Keshav FirstFragment: onStop --------------------------- FirstFragment
E/Keshav FirstFragment: onDestroyView -------------------- FirstFragment
E/Keshav SecondFragment: onCreateView
E/Keshav SecondFragment: onActivityCreated
E/Keshav SecondFragment: onStart
E/Keshav SecondFragment: onResume
分崩离析
分崩离析
流行音乐片段2
流行音乐片段1
虽然这是一个已经回答过的老问题,但也许下面的例子可以补充已被接受的答案,对一些像我这样的Android新程序员来说也很有用
选项1-“addToBackStack()”从未使用过
btn_one.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getActivity(),"Click First Fragment",Toast.LENGTH_LONG).show();
Fragment fragment = new SecondFragment();
getActivity().getSupportFragmentManager().beginTransaction()
// .add(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
.replace(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}
});
E/Keshav SecondFragment: onAttach
E/Keshav SecondFragment: onCreate
E/Keshav FirstFragment: onPause -------------------------- FirstFragment
E/Keshav FirstFragment: onStop --------------------------- FirstFragment
E/Keshav FirstFragment: onDestroyView -------------------- FirstFragment
E/Keshav SecondFragment: onCreateView
E/Keshav SecondFragment: onActivityCreated
E/Keshav SecondFragment: onStart
E/Keshav SecondFragment: onResume
案例1A-添加、删除和单击“上一步”按钮
案例1B-添加、替换和单击后退按钮
选项2始终使用“addToBackStack()”
btn_one.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getActivity(),"Click First Fragment",Toast.LENGTH_LONG).show();
Fragment fragment = new SecondFragment();
getActivity().getSupportFragmentManager().beginTransaction()
// .add(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
.replace(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}
});
E/Keshav SecondFragment: onAttach
E/Keshav SecondFragment: onCreate
E/Keshav FirstFragment: onPause -------------------------- FirstFragment
E/Keshav FirstFragment: onStop --------------------------- FirstFragment
E/Keshav FirstFragment: onDestroyView -------------------- FirstFragment
E/Keshav SecondFragment: onCreateView
E/Keshav SecondFragment: onActivityCreated
E/Keshav SecondFragment: onStart
E/Keshav SecondFragment: onResume
案例2A-添加、删除和单击后退按钮
案例2B-添加、更换、删除并单击“上一步”按钮
Fragment1: onPause
Fragment1: onStop
Fragment1: onDestroyView
Fragment1: onDestroy
Fragment1: onDetach
Fragment1: onAttach
Fragment1: onCreate
Fragment1: onCreateView
Fragment1: onActivityCreated
Fragment1: onStart
Fragment1: onResume
Fragment2: onAttach
Fragment2: onCreate
Fragment2: onCreateView
Fragment2: onActivityCreated
Fragment2: onStart
Fragment2: onResume
Fragment2: onPause
Fragment2: onStop
Fragment2: onDestroyView
Fragment2: onDestroy
Fragment2: onDetach
Fragment1: onPause
Fragment1: onStop
Fragment1: onDestroyView
Fragment1: onDestroy
Fragment1: onDetach
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
add Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment B is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy()
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() App is closed, nothing is visible
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(replace Fragment C)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy()
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() App is closed, nothing is visible
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
add Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() Fragment B is visible
(Back button clicked)
Fragment C : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment B is visible
(Back button clicked)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment A is visible
(Back button clicked)
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(replace Fragment C)
Fragment B : onPause() - onStop() - onDestroyView()
Fragment A : onPause() - onStop() - onDestroyView()
Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() Activity is visible
(Back button clicked)
Fragment C : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onCreateView() - onActivityCreated() - onStart() - onResume()
Fragment B : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(Back button clicked)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment A is visible
(Back button clicked)
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B w/o: onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
add Fragment C w/o: onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Fragment B is visible
(Back button clicked)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
Activity : onCreate() - onStart() - onResume() Activity is visible
add Fragment A : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
add Fragment B w/o: onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment B is visible
(replace Fragment C)
Fragment B : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onPause() - onStop() - onDestroyView()
Fragment C : onAttach() - onCreate() - onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
remove Fragment C : onPause() - onStop() - onDestroyView() Activity is visible
(Back button clicked)
Fragment C : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment C is visible
(Back button clicked)
Fragment C : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach()
Fragment A : onCreateView() - onActivityCreated() - onStart() - onResume() Fragment A is visible
(Back button clicked)
Fragment A : onPause() - onStop() - onDestroyView() - onDestroy() - onDetach() Activity is visible
(Back button clicked)
Activity : onPause() - onStop() - onDestroy() App is closed, nothing is visible
btn_one.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getActivity(),"Click First
Fragment",Toast.LENGTH_LONG).show();
Fragment fragment = new SecondFragment();
getActivity().getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
// .replace(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}
});
E/Keshav SecondFragment: onAttach
E/Keshav SecondFragment: onCreate
E/Keshav SecondFragment: onCreateView
E/Keshav SecondFragment: onActivityCreated
E/Keshav SecondFragment: onStart
E/Keshav SecondFragment: onResume
btn_one.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(getActivity(),"Click First Fragment",Toast.LENGTH_LONG).show();
Fragment fragment = new SecondFragment();
getActivity().getSupportFragmentManager().beginTransaction()
// .add(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
.replace(R.id.fragment_frame, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}
});
E/Keshav SecondFragment: onAttach
E/Keshav SecondFragment: onCreate
E/Keshav FirstFragment: onPause -------------------------- FirstFragment
E/Keshav FirstFragment: onStop --------------------------- FirstFragment
E/Keshav FirstFragment: onDestroyView -------------------- FirstFragment
E/Keshav SecondFragment: onCreateView
E/Keshav SecondFragment: onActivityCreated
E/Keshav SecondFragment: onStart
E/Keshav SecondFragment: onResume
getSupportFragmentManager()
.beginTransaction()
.add(R.id.fragmentContainer, fragment, "TAG")
.addToBackStack("TAG")
.commit();
getSupportFragmentManager()
.beginTransaction()
.add(R.id.fragmentContainer, fragment, "TAG")
.commit();